body {
  height: 2000px;
  margin: 0;
  padding: 0;
}
.demo {
  width: 414px;
  margin: 0 auto;
  padding-bottom: 500px;
  h6 {
    font-weight: 400;
    position: sticky;
    z-index: 1;
    top: 0;
    margin: 0;
    padding: 3px 1rem;
    color: #444444;
    background-color: #eeeeee;
  }

  ul {
    position: relative;
    margin: 0;
    padding: 0;
    list-style: none;
  }

  li {
    font-size: 14px;
    float: none;
    width: auto;
    padding: 5px 1rem;
    border-top: 1px solid #f5f5f5;
  }
}
